Purpose
To describe patient demographics and microbiological features of patients with clinically diagnosed endophthalmitis following intravitreal injection
Methods
Retrospective review of consecutive cases of endophthalmitis seen at a university referral center between January 2005 and August 2012
Results
Thirty one eyes from 31 patients presented clinically diagnosed endophthalmitis following intravitreal injection in the study period. Most patients were women (58%) and the mean age was 68 ± 10.34 years old. The majority of the patients received injections of bevacizumab (61.3%) followed by steroids (16.12%), ranibizumab (3.22%) and miscellaneous (19.35%). Overall, the positivity of bacterial culture was 48.4% (15 out of 31 patients). The higher culture positivity was achieved for vitreous from vitrectomy (55.5%; 5/9) and vitreous tap samples (47.8%; 11/23). Aqueous humor was culture positive in 14.3% (2/14) of the samples. At the time of sample collection, at least 9 out of 15 patients were in use of topical fluoroquinolone (for the remaining information was not available). The most common organism isolated was coagulase-negative Staphylococci - CoNS (73.3%; 11/15) followed by S. aureus (20%; 3/15) and viridans group Streptococci (6.6%; 1/15). Gatifloxacin (GAT) and moxifloxacin (MOX) susceptibility rate was 80% (MIC90 2 µg/mL) among all bacterial isolates. All S. aureus isolates were susceptible to fourth-generation fluoroquinolone, methicillin and vancomycin. For CoNS, 72.7% of isolates were susceptible to GAT and MOX (MIC90 4µg/mL for both). The frequency of methicillin-resistant CoNS (MRCoNS) was 36.3% (4/11). Only MRCoNS isolates demonstrated resistance to fourth-generation fluoroquinolones (75%; 3/4). All CoNS isolates were susceptible to vancomycin.
Conclusions
Culture-proven endophthalmitis following intravitreal injection was documented in the last 7 years for 15 patients in our setting. Staphylococci remained as the main causative organism and was isolated even from patients using post-injection topical fluoroquinolones. The frequency of endophthalmitis was higher among the patients that received bevacizumab intravitreal injection, probably due to the greater number of this type of injection.
Keywords: 513 endophthalmitis •
561 injection •
688 retina